Question

The unit of length convenient on the atomic scale is known as an angstrom and is denoted by Å: 1Å = 10^-10 m. The size of a hydrogen atom is about 0.5 Å. What is the total atomic volume in m³ of a mole of hydrogen atoms?

Answer 1

Radius of a hydrogen atom = r = 0.5 Å = 0.5 × 10^-10m

Volume of a mole of hydrogen atoms = Volume of a hydrogen atom × Number of hydrogen atoms in 1 mole

= (4/3)πr³ × N_A

= (4/3) × 3.14 × ( 0.5 × 10^-10)³ × 6.022 × 10²³

= 3 × 10^-7 m³ (rounded off to 1 significant figure)